一种电网电压过零点精确锁相方法的研究

针对电网电压过零锁相时存在的零点漂移和相位延迟问题,提出了一种电网电压过零点精确锁相的方法。通过软件PQ滤波去除ADC采样结果中的零点漂移;通过人为设定一个过零点锁相提前量,可提前预见到电网电压的过零点;然后通过软件自适应补偿算法,实现电网电压过零点的精确检测。详细阐述了该方法的原理和计算过程,在无整流器自充电电压暂变补偿装置上的实验结果证实了所提方法的正确性。

Study on precise phase lock techniques used for grid voltage zero-crossing

To cope with the problem of the voltage-zero drift and the phase delay in zero crossing phase lock, a precise phase lock technique used for grid voltage zero-crossing is proposed. This method removes the zero drift in the ADC sampling result by using PQ filtering; and then sets a zero phase locking schedule artificially, in order to foresee the zero-crossing point of the grid voltage; lastly, through software self-adaptive compensation algorithm, the precise detection of grid voltage zero point can be realized. The design principle and calculation process of this method are introduced. This method is proved to be correct by experiment on the platform of the self-charging voltage sag compensator without rectifier.